Endoscopic hook blade and use thereof

ABSTRACT

An endoscopic surgical blade is disclosed. The blade is of a hook design, having an upper cutting surface located on the trailing edge of an arm and a lower cutting surface on the upper edge of the main body of the blade. The blade is part of an endoscopic knife assembly which also contains a knife tube and alignment ring. The endoscopic knife assembly is for use in endoscopic surgery by insertion of the assembly through a slotted cannula. The knife tube is hollow and allows the insertion of an endoscope for viewing of the surgical procedure. A method for a performing an operative procedure on a target tissue in a subject using an endoscopic knife assembly having a hook blade is also described.

FIELD

The present application relates to medical devices and, in particular,to a surgical blade for endoscopic operations.

BACKGROUND

Endoscopic surgery is a minimally invasive surgical procedure that isperformed through small incisions or natural body openings. Anendoscopic procedure typically involves use of specialized devices andremote-control manipulation of instruments with indirect observation ofthe surgical field through an endoscope or similar device. Comparing toopen surgery, endoscopic surgery may result in shorter hospital stays,or allow outpatient treatment.

Among more recent developments and advances in endoscopic surgicalprocedures, arthroscopic surgery employing the use of endoscopic deviceshas found widespread application. For example, endoscopic procedureshave been used in effectuating carpal tunnel release with endoscopicinstruments. However, there always exists a need to further improve theutility of the instrument, reduce the cost and improve the performanceof endoscopic surgical procedures.

SUMMARY

One aspect of the present application relates to a hook blade for anendoscopic knife assembly. The hook blade comprises an arm having aforward edge, a trailing edge and an upper cutting surface located onthe trailing edge; a main body having an upper edge, a lower edge, adistal section, a proximate section, and a lower cutting surface locatedon the upper edge of the distal section; wherein the distal section ofthe main body angles downward from the proximate section of the mainbody, forming a downward angle with the proximate section of the mainbody, wherein the arm protrudes from the distal section of the main bodyand extends back towards the main body in a hook-like manner, forming ahook angle with the proximate section of the main body, and wherein theupper cutting surface and the lower cutting surface meets at a crotchforming a cutting angle between the two cutting surfaces.

Another aspect of the present application relates to an endoscopic knifeassembly. The endoscopic knife assembly comprises a knife tube having adistal end and a proximate end, a hook blade attached to the distal end,and an alignment ring attached near the proximate end.

Yet another aspect of the present application relates to an instrumentkit for implementing an endoscopic surgical procedure. The instrumentkit comprises a slotted cannula for endoscopic surgical procedures andan endoscopic knife assembly comprising a hook blade, a knife tube andan alignment ring. The endoscopic knife assembly is insertable into theslotted cannula.

Still another aspect of the present application relates to a method fora performing an operative procedure on a target tissue in a subject,comprising: making an incision to establish an entry portal, inserting acannula having open proximal and distal ends, inserting an endoscopeinto the cannula, said endoscope comprising an endoscopic knife assemblyhaving a hook blade, advancing said endoscope so that the hook blademoves distal to and is in contact with the target tissue, operativelyengaging the target tissue with the hook blade, and withdrawing the hookblade back towards the cannula to perform the operative procedure on thetarget tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

The present application can be better understood by reference to thefollowing drawings. The drawings are merely exemplary to illustratecertain features that may be used singularly or in combination withother features and the present application should not be limited to theembodiments shown.

FIGS. 1A-F illustrate a hook blade component of an endoscopic knifeassembly. FIG. 1A is a perspective view showing the hook bladecomponent. FIG. 1B depicts a side view of the hook blade component,showing the cutting surfaces, the transition where the blade is joinedto the knife tube and the taper at the end of the blade. FIG. 1C is aperspective view showing a top view of the hook blade. FIG. 1D depicts aside view of the hook blade component. FIG. 1E is a cross section viewof the hook blade at the bisecting line 3 in FIG. 1D depicting anexemplary angle of a cutting surface of the blade component. FIG. 1F isa perspective view of the hook blade from the back depicting the widthof the blade, the transition and the extension of the lower cuttingsurface below the transition.

FIGS. 2A-D illustrate an endoscopic knife assembly. FIG. 2A is aperspective view of the endoscopic knife assembly from the side. FIG. 2Bis a perspective view of the endoscopic knife assembly from the top.FIG. 2C is a perspective view of the endoscopic knife assembly from thebottom. FIG. 2D is a perspective view of the endoscopic knife assemblyfrom the front.

FIGS. 3A-E illustrate the knife tube component of the endoscopic knifeassembly. FIG. 3A is a magnified view from the side of the proximate endof a knife tube, showing the slots and the flared end. FIG. 3B is aperspective view of the proximate end of a knife tube, showing the slotsand the flared end. FIG. 3C is a perspective view from the bottom of aknife tube, shown at an angle. FIG. 3D is a perspective view from theside of a knife tube. FIG. 3E is a perspective view from the top orbottom of a knife tube.

FIGS. 4A-D illustrate the alignment ring component of the endoscopicknife assembly. FIG. 4A is a perspective view at an angle as seen fromthe bottom, showing the flattened bottom face of the alignment ring.FIG. 4B is a perspective view at an angle as seen from the front or backface of the alignment ring. FIG. 4C is a perspective view seen from theside of the alignment ring. FIG. 4D is a perspective view seen from thetop of the alignment ring.

DETAILED DESCRIPTION

This description is intended to be read in connection with theaccompanying drawings, which are to be considered part of the entirewritten description of this application. The drawing figures are notnecessarily to scale and certain features of the application may beshown exaggerated in scale or in somewhat schematic form in the interestof clarity and conciseness. In the description, relative terms such as“front,” “back,” “up,” “down,” “top,” “bottom,” “upper,” “lower,”“distal,” and “proximate” as well as derivatives thereof, should beconstrued to refer to the orientation as then described or as shown inthe drawing figure under discussion. These relative terms are forconvenience of description and noi malty are not intended to require aparticular orientation. Terms concerning attachments, coupling and thelike, such as “connected,” “mounted,” and “attached,” refer to arelationship wherein structures are secured or attached to one anothereither directly or indirectly through intervening structures, as well asboth movable or rigid attachments or relationships, unless expresslydescribed otherwise.

In endoscopic surgery, it is sometimes undesirable or impractical toperform a cut of a tissue using a blade that is pushed forward outwardfrom the end of a cannula to make the cut in a forward direction. Thismay be due to a variety of factors including, but not limited to, theproximity of the tissue to be cut (target tissue) to another tissue oran organ distal to the target tissue from that cannula, a lack oftension in the target tissue that would allow the blade to push thetarget tissue away from the cannula or the flexibility of the targettissue, for example.

Accordingly, the present application fills a need in the art byproviding a “hook blade.” The blade described herein is a low-profileblade that lacks forward facing cutting surfaces. The cutting surfacesof the blade are instead located on the trailing edge of an arm thatprotrudes upward from the main body of the blade (upper cutting surface)and on the forward portion of the upper surface of the main body of theblade (lower cutting surface). The arm of the blade is additionallyangled back towards the main body of the blade, forming a hook.Additionally, that forward portion of the main body of the bladecomprising the lower cutting surface is angled downward in front of theknife tube upon which it is mounted.

This downward angle allows the hook blade described herein to maintain alow profile such that it can be used with a slotted cannula and does notrequire a mechanical means for extending the blade out the side of theknife tube, as required by some other rearward-facing endoscopic cuttingdevices. The presently described low-profile hook blade thereforeprovides several advantages over other devices including, but notlimited to, the lack of moving parts required to raise the blade out ofthe side of the knife tube reducing the risk of malfunction or failureof the cutting instrument. An additional advantage of the presentlow-profile hook blade design is that the lack of said moving parts andthe obligatory linkages and apparatus required to operate the extensionof the blade allows the knife tube to be hollow. This allows thepractitioner to extend an endoscopic camera through the hollow knifetube to allow direct visualization of the tissue and blade before,during and after the cutting of the target tissue.

The design of the present low-profile hook blade is such that it isusable in endoscopic surgery in a manner that allows the practitioner toextend the blade through the cannula and past the target tissue withoutdamage to surrounding tissue and/or organs. The blade is then positioneddistal to the target tissue such that the target tissue can be drawninto the hook formed by the upper and lower cutting surfaces. The hookblade apparatus is then drawn back towards and into the cannula toeffect a cut of the target tissue. The downward angle of the lowercutting surface portion of the main body of the blade and the backwardangle of the arm assist in drawing the target tissue into the hookstructure of the blade.

One aspect of the present application relates to a hook blade for anendoscopic knife assembly, comprising: an arm having a forward edge, atrailing edge and an upper cutting surface located on the trailing edge;a main body having an upper edge, a lower edge, a distal section, aproximate section, and a lower cutting surface located on the upper edgeof the distal section; wherein the distal section of the main bodyangles downward from the proximate section of the main body, forming adownward angle with the proximate section of the main body, wherein thearm protrudes from the distal section of the main body and extends backtowards the main body in a hook-like manner, forming a hook angle withthe proximate section of the main body, and wherein the upper cuttingsurface and the lower cutting surface meets at a crotch forming acutting angle between the two cutting surfaces.

In one particular embodiment, the hook angle is between about 55 degreesand about 75 degrees. In a further embodiment, the hook angle is about65 degrees.

In another particular embodiment, the cutting angle is between about 40degrees and about 60 degrees. In a further embodiment, the cutting angleis about 50 degrees.

In another particular embodiment, the downward angle is between about150 degrees and about 175 degrees. In a further embodiment, the downwardangle is between about 165 degrees.

In one particular embodiment, the proximate section of the main body hasa tapered end.

In another particular embodiment, the main body comprises a notch on thelower edge to engage with a knife tube.

In another particular embodiment, the arm comprises an upper radius onthe upper end of the forward edge to prevent the forward edge fromdamaging tissue as the hook blade is advanced from a cannula. In afurther embodiment, the arm further comprises a lower radius on thelower end of the forward edge to prevent the forward edge from damagingtissue as the hook blade is advanced from a cannula.

In another particular embodiment, the hook blade has a total verticalheight in the range of about 4 mm to about 5 mm.

Another aspect of the present application relates to an endoscopic knifeassembly, comprising: a knife tube having a distal end and a proximateend; a hook blade attached to the distal end; and an alignment ringattached near the proximate end, wherein the hook blade comprises an armhaving a forward edge, a trailing edge and an upper cutting surfacelocated on the trailing edge; a main body having an upper edge, a loweredge, a distal section, a proximate section, and a lower cutting surfacelocated on the upper edge of the distal section; wherein the distalsection of the main body angles downward from the proximate section ofthe main body, forming a downward angle with the proximate section ofthe main body, wherein the arm protrudes from the distal section of themain body and extends back towards the main body in a hook-like manner,forming a hook angle with the proximate section of the main body, andwherein the upper cutting surface and the lower cutting surface meets ata crotch forming a cutting angle between the two cutting surfaces.

In another particular embodiment, the knife tube comprises one or moreslots at the proximate end for the attachment of a locking assembly tothe knife tube and alignment ring.

In another particular embodiment, the slots are located on a plane thatis perpendicular to the hook blade attached to the distal end of theknife tube.

In another particular embodiment, the knife tube is marked on the top orside surface with gradations.

In another particular embodiment, the alignment ring comprises aflattened surface that is positioned perpendicular to the hook bladeattached to the distal end of the knife tube.

In another particular embodiment, the hook blade is welded to the knifetube.

Another aspect of the present application relates to an instrument kitfor implementing an endoscopic surgical procedure comprising: anendoscopic knife assembly comprising a hook blade, a knife tube and analignment ring, wherein the blade comprises an upper cutting surfacelocated on a trailing edge of an arm and a lower cutting surface locatedon an upper edge of a main body of the blade, the cutting surfacesmeeting at an angle at a crotch; and a slotted cannula for endoscopicsurgical procedures, wherein the endoscopic knife assembly is insertableinto the slotted cannula.

In one particular embodiment, the main body of the blade comprises anotch on a lower edge of the main body to engage with the knife tube.

Another aspect of the present application relates to a method for aperforming an operative procedure on a target tissue in a subject,comprising: making an incision to establish an entry portal, inserting acannula having open proximal and distal ends, inserting an endoscopeinto the cannula, said endoscope comprising an endoscopic knife assemblyhaving a hook blade, advancing said endoscope so that the hook blademoves distal to and is in contact with the target tissue, operativelyengaging the target tissue with the hook blade, and withdrawing the hookblade back towards the cannula to perform the operative procedure on thetarget tissue.

In one particular embodiment, the operative procedure is an endoscopicsurgical procedure selected from the group consisting of carpal tunnelrelease, cubital tunnel release, plantar fascia release, lateral releasefor patella realignment, release of the extensor tendons, release of theposterior and other compartments of the leg, and forearm fascialrelease.

In another particular embodiment, the cannula is a clear cannula.

In another particular embodiment, the cannula comprises an open slotextending along the length of the cannula.

In another particular embodiment, the inserting of said endoscopecomprising an endoscopic knife assembly having a hook blade is precededby the insertion of another endoscope comprising a means forvisualization of the target tissue. In a further embodiment, the cannulais a clear cannula. In a further embodiment, the method furthercomprises visualization of anatomic structures surrounding the cannula.

In another particular embodiment, the establishing an entry portalcomprises making an incision.

One aspect of the present application is a scope-mounting blade orendoscopic knife assembly for endoscopic surgery. The knife assemblycomprises a hook blade, a knife tube and an alignment ring. The assemblyis assembled by affixing the alignment ring and the blade onto the knifetube.

The hook blade is made from materials commonly used for surgical bladesor scalpels, such materials include, but are not limited to, hardenedand tempered steel, stainless steel, high carbon steel, titanium, alloysand ceramic. In one embodiment, the blade is made from SAE 440Astainless steel. In a preferred embodiment, the blade is made fromHitachi GIN-5 SST-MODIFIED 440-A stainless steel. The blade isoptionally flash electropolished. The cutting edges are machine finishedand must be sharp. In a particular embodiment, the steel of the blade isheat-treated to Rockwell C hardness of about 50-72. In a more particularembodiment, the steel of the blade is heat-treated to Rockwell Chardness of 58-64.

An embodiment of the hook blade is shown in FIGS. 1A-1F. As shown inFIG. 1A, the hook blade 100 comprises an arm 50 having a forward edge 52and a trailing edge 54, and a main body 60 having an upper edge 62 and alower edge 64. The upper cutting surface 1 and the lower cutting surface2 are formed on the trailing edge 54 of the arm 50 and the upper edge 62of the main body. The arm 50 is oriented in a hook configurationtrailing an arm 50 of the blade 100. The upper cutting surface 1 and thelower cutting surface 2 meet at a central crotch 5 and form a cuttingangle 4 between the two surfaces. The cutting surfaces 1 and 2 are sharpcutting surfaces, while no other surfaces of the hook blade 100 areintended to be cutting surfaces.

In one embodiment, the cutting angle 4 is between about 40 and about 60degrees. In another embodiment, the cutting angle 4 is between about 45and about 55 degrees. In another embodiment, the cutting angle 4 isabout 50 degrees.

Referring now to FIG. 1B, the distal section 80 of the main body 60extends downward and forms a downward angle 8 with the proximal section70 of the main body 60. In certain embodiments, the interior angle 8 isbetween about 150 and about 175 degrees. In other embodiments, theinterior angle 8 is between about 160 and about 170 degrees. In yetanother embodiment, the interior angle 8 is about 165 degrees.

The arm 50 protrudes upward from the distal section 80 and angles backtowards the main body in a hook-like manner, forming a hook angle 56with the proximate section 70 of the main body 60. In one embodiment,the hook angle 56 is between about 55 and about 75 degrees. In anotherembodiment, the hook angle 56 is between about 60 and about 70 degrees.In another embodiment, the hook angle 56 is about 65 degrees.

In one embodiment, the width 6 of the arm 50 is between about 1.5 andabout 2.0 mm. In another embodiment, the width 6 is between about 1.65and 1.85 mm. In another embodiment, the width 6 is about 1.778 mm.

Referring again to FIG. 1B, in certain embodiments, the upper end of theforward edge 52 of the arm 50 has an upper radius 10 in order to preventit from damaging tissue as the hook blade 100 is advanced from acannula. In one embodiment, the upper radius 10 has a radius measurementof between about 1.0 mm and 2.5 mm. In another embodiment, the upperradius 10 has a radius measurement of about 2.032 mm.

In other embodiments, the lower end of the forward edge 52 of the arm 50has a lower radius 11 in order to prevent it from damaging tissue as thehook blade apparatus is advanced from the cannula. In one embodiment,the lower radius 11 has a radius measurement between about 4 mm and 10mm. In another embodiment, the lower radius 11 has a radius measurementof about 0.635 mm.

In certain embodiments, the distance 12 between the upper radius 10 andthe lower radius 11 on the forward edge 52 of the arm 50 is betweenabout 2.5 mm and 2.8 mm. In one embodiment, the distance 12 is about2.62 mm.

Referring again to FIG. 1B, in certain embodiments, the arm 50 is angledback such that the horizontal distance 13 in a plane with the main body60 of the blade 100 from the most forward point on the lower radius 11to the top and farthest back point on cutting surface 1 is between about3.4 and 3.8 mm. In one embodiment, the horizontal distance 13 is betweenabout 3.5 and 3.7 mm. In another embodiment, the horizontal distance 13is about 3.63 mm.

In certain embodiments, the height 15 of the proximate section 70 of themain body 60 is between about 1 mm and about 1.8 mm. In one embodiment,the height 15 is between about 1.2 mm and about 1.6 mm. In anotherembodiment, the height 15 is between about 1.3 mm and about 1.4 mm. Inanother embodiment, the height 15 is about 1.42 mm.

In certain embodiments, the vertical distance 16 between the top andfarthest back point on cutting surface 1 and the bottom edge 64 of theproximate section 70 is between about 2.4 mm and about 3.0 mm. In oneembodiment, the vertical distance 16 is between about 2.6 mm and about2.8 mm. In another embodiment, the vertical distance 16 is about 2.69mm. In order to insure that, during manufacture, the hook blade 100 isconsistently joined to the knife tube 200 in the same location, thelower edge 64 of the main body 60 comprises a notch 66. During assemblyof the endoscopic knife assembly, the notch 66 is butted against thefront of the knife tube. Following the positioning of the blade on theknife tube, the blade 100 is laser welded all around to the knife tube.In one embodiment, the strength of the weld is tested by applying torqueto the unit, for example about 10 in-lbs of torque. In certainembodiments, the depth 21 of the notch 66 is between about 0.025 mm andabout 0.18 mm. In one embodiment, the depth 21 of the notch 66 isbetween about 0.051 mm and about 0.1524 mm. In another embodiment, thedepth 21 of the notch 66 is about 0.102 mm.

Additionally, in certain embodiments, the horizontal distance 22 betweenthe notch 66 and the focus of angle 8 is between about 1.6 mm and about2.1 mm, preferably about 1.85 mm. In another embodiment, the horizontaldistance 23 between the notch 66 and the top and farthest back point oncutting surface 1 is between about 3.0 mm and about 7.0 mm, preferablybetween about 4.0 mm and about 5.5 mm, and more preferably about 4.78 mmor 4.826 mm. In yet another embodiment, the horizontal distance 24between the notch 66 and the top and farthest back point on cuttingsurface 2 is between about 2.8 mm and about 3.3 mm, preferably about3.05 mm.

In order to prevent the hook blade from catching on the interior surfaceof the cannula when the blade 100 is drawn backwards through the cannulatube, the blade 100 has a tapered trailing edge 27. In one embodiment,the horizontal length of the tapered trailing edge 27 is between about2.5 mm to about 10 mm, more particularly about 3.0 mm to about 5.0 mm.In another embodiment, the horizontal length of the tapered trailingedge 27 is about 3.81 mm. In some embodiments, the tapered trailing edge27 has a blunt end, with a depth 28 of between about 0.1 mm to about 0.4mm, more particularly about 0.254 mm.

Referring now to FIG. 1C, in certain embodiments, the total length 14 ofthe blade 100 from the leading point of the lower radius 11 to thetrailing end of the proximate section 70 is between about 15 mm andabout 40 mm. In one embodiment, the total length 14 of the blade 100 isbetween about 20 mm and about 330 mm. In another embodiment, the totallength 14 of the blade 100 is about 26.4 mm.

Referring now to FIG. 1D, in certain embodiments, the vertical distance19 between the center of the lower radius 11 and the bottom edge 64 ofthe main body 60 (where it is affixed to the knife tube) is betweenabout 0.9 mm and about 1.2 mm. In one embodiment, the vertical distance19 is between about 1.0 mm and about 1.1 mm. In another embodiment, thevertical distance 19 is about 1.04 mm.

In some embodiments, the upper cutting surface 1 and lower cuttingsurface 2 form a sharp angle at the crotch 5. In other embodiments, theupper cutting surface 1 and lower cutting surface 2 meet at the crotch 5with a ground curved corner. In one embodiment, the grinding of theupper cutting surface 1 and lower cutting surface 2 cutting surfaceswhere they meet at the crotch 5 has a maximum radius of about 0.65 mm.In a particular embodiment, the grinding at the crotch 5 has a maximumradius of about 0.5 mm. In a more particular embodiment, the grinding atthe crotch 5 has a maximum radius of 0.381 mm.

Referring again to FIG. 1D, in one embodiment, the horizontal distance25 between the notch 66 and the focus of radius 11 is between about 7.5mm and about 8.0 mm, preferably about 7.77 mm.

In order to maintain uniform measurement of the gradations on the knifetube 200 and the cutting surfaces of the hook blade 100, the horizontaldistance 26 between the notch 66 and the crotch 5 is preferably 5.41 mm.Alternatively, a horizontal distance 26 can be chosen for a particularmodel or lot of the hook blade 100 within a range of about 2.5 mm toabout 10 mm.

Referring again to FIG. 1D, in a particular embodiment, the verticaldistance 20 between the crotch 5 and the bottom edge 64 of the main body60 (where it is affixed to the knife tube) is between about 0.6 mm andabout 0.9 mm. In another embodiment, the vertical distance 20 is betweenabout 0.7 mm and about 0.8 mm. In a more particular embodiment, thevertical distance 20 is about 0.762 mm.

FIG. 1E shows a cross-sectional view of the distal section 80 of themain body 60 from line 3-3 in FIG. 1D. In one embodiment, thecross-sectional depth 82 of the distal section 80 is between about 1.5mm and 2.0 mm. In another embodiment, the cross-sectional depth 82 ofthe distal section 80 is between about 1.6 mm and 1.9 mm. In anotherembodiment, the cross-sectional depth 82 of the distal section 80 isabout 1.778 mm.

Similarly, in one embodiment, the cross-sectional depth of the arm 50(i.e., the cross-section from line 3′-3′ in FIG. 1D) is between about1.5 mm and 2.0 mm. In another embodiment, the cross-sectional depth 82of the arm 50 is between about 1.6 mm and 1.9 mm. In another embodiment,the cross-sectional depth 82 of the arm 50 is about 1.778 mm.

Referring again to FIG. 1E, in certain embodiments, the cutting surfaces1 and 2 each contains a subsurface a and a subsurface b that forms asurface angle 29 with the subsurface a. In certain embodiments, thecutting angle 29 of the cutting surfaces 1,2 is between about 35 degreesand about 45 degrees, more particularly about 40 degrees. In certainembodiments, the subsurfaces a and b each have a width 30 that isbetween about 0.8 mm and about 1.0 mm, more particularly about 0.91 mm.

Referring now to FIG. 1F, in certain embodiments, the total verticalheight 17 of the hook blade 100 from the bottom of radius 11 to the topand farthest back point on cutting edge 1 is between about 4.0 mm andabout 5.0 mm. In one embodiment, the total vertical height 17 is betweenabout 4.35 mm and about 4.65 mm. In another embodiment, the totalvertical height 17 is about 4.445 mm.

In certain embodiments, the thickness 18 of the hook blade 100 isbetween about 0.50 mm and about 0.75 mm. In one embodiment, thethickness 18 of the hook blade 100 is between about 0.60 mm and about0.67 mm. In another embodiment, the thickness 18 of the hook blade isabout 0.635+/−0.013 mm.

Referring again to FIG. 1F, in certain embodiments, the distal section80 of the main body 60 extends below the bottom edge 64 of the main body60 (where it affixes to the knife tube) a distance 9 of between about1.5 and 1.9 mm. In another embodiment, the distance 9 is between about1.6 and about 1.8 mm. In another embodiment, the distance 9 is about1.68 mm.

FIGS. 2A-2D show a hook-blade assembly 300 with a hook blade 100 mountedon a knife tube 200. As shown in FIG. 2A, the hook blade 100 is attachedto the knife tube 200, such that the notch 66 of the blade 100 is buttedup against the distal end 202 of the knife tube 200. In one embodiment,the hook blade 100 is welded to the knife tube 200.

In one embodiment, the top and farthest back point of upper cuttingsurface 1 extends a distance 31 of about 3.0 mm to about 7.0 mm, moreparticularly about 4.0 mm to about 5.5 mm forward of the knife tube. Ina most particular embodiment, the distance 31 is about 4.826 mm or 4.78mm.

In a particular embodiment, the length 32 of the knife tube 200 is fromabout 100 mm to about 140 mm, preferably from about 114.3 mm to about119.4 mm. In a more preferred embodiment, the length 32 of the knifetube 200 is about 116.84 mm.

The knife tube 200 can optionally be marked on the top or side surfacewith gradations as exemplified in FIG. 2B to show the distance to thecrotch 5 of the cutting surfaces. For example, major gradations 34 canbe made to show each centimeter in distance from the crotch 5, withminor gradations 36 between them to show each 1, 2, 2.5 or 5millimeters. While the gradations can be applied to the knife tube byany means known in the art, it is preferable to lasermark the gradationson the knife tube 200 for accuracy and permanence. Additionally, theknife tube 200 can also be marked in a similar manner with additionalinformation, for example on the bottom or a side surface of the knifetube 200. Exemplary markings may include, but are not limited to, amaker's mark, part number, lot number and an indication that theendoscopic knife assembly is intended for only a single use (see, e.g.,FIG. 2C).

Referring again to FIG. 2A, an alignment ring 250 is affixed near theproximate end of the knife tube 200. In one embodiment, the alignmentring 250 is affixed in position on the knife tube 200 using USP Class VIgamma irradiation and steam resistant epoxy adhesive during assembly.Preferably, a two part epoxy such as MASTERBOND EP42 HT™ or ARMSTRONGC-7™, or a suitable equivalent thereof is used. In one embodiment, thedistance 33 between the alignment ring 250 and the proximate end of theknife tube 200 is between about 15 mm and about 25 mm. In anotherembodiment, the distance 33 is between about 18.67 mm and about 19.43mm. In another embodiment, the distance 33 is about 19.05+/−0.38 mm.

The knife tube further comprises slots 37 in the proximate end that arepositioned on the sides of the knife tube 200, perpendicular to theblade mounted on the top of the knife tube. The slots 37 preferablyextend forward to where the alignment ring 250 is affixed to the knifetube 100.

The slots and alignment ring provide an attachment point for a lockingdevice, in order to mount an endoscope to the scope-mounting blade orendoscopic knife assembly.

FIGS. 3A-E show perspective views of a knife tube 200 without an affixedblade or alignment ring and without gradations. Referring now to FIG.3A, in one embodiment, the outer diameter 38 of the knife tube 200 isbetween about 2.8 mm and about 3.6 mm, preferably between about 3.073 mmand about 3.175 mm. In a more preferred embodiment, the outer diameter38 is about 3.124 mm.

Referring again to FIG. 3A, in another embodiment, the knife tube 200has a flared proximate end 40. In one embodiment, about 0.2 to about 0.5most proximate millimeters of the knife tube 200 are flared. In anotherembodiment, about the 0.381 most proximate millimeters of the knife tube200 are flared. In another embodiment, the flared proximate end 40 has aflare angle 41 of about 20 to 40 degrees, more preferably about 30degrees. In still another embodiment, the outer diameter 42 of theflared proximate end 40 of the knife tube is about 0.25 mm to about 0.45mm, more particularly about 0.356 mm.

Referring now to FIG. 3B, the inner diameter 39 of the knife tube 200 issuch that an endoscope camera can be inserted into the knife tube inorder to show the blade and the target tissue during a procedure. In oneembodiment, the inner diameter 39 is between about 2 mm and about 3.5mm. In a particular embodiment, the inner diameter 39 is between about2.769 mm and about 2.87 mm. In a more particular embodiment, the innerdiameter 39 is about 2.819 mm.

In one embodiment, the slots 37 have a width 43 of between about 0.4 mmand about 1.1 mm wide, more particularly between about 0.533 mm andabout 0.914 mm wide. Even more particularly, the width 43 of the slotsis about 0.6604 mm.

FIGS. 4A-D show an embodiment of the alignment ring 250 of theendoscopic knife assembly of the application. Referring now to FIG. 4A,in one embodiment, the alignment ring 250 has a flattened surface 252that, when the alignment ring 250 is affixed to the knife tube 200, isoriented on the bottom of the knife tube 200, i.e., opposite of themounting of the blade 100. When the endoscopic knife assembly is fullyassembled, the flattened surface 252 of the alignment ring forms a rightangle with the vertical orientation of the affixed blade 100, asdepicted in FIG. 4B.

In one embodiment, the inner diameter 44 of the alignment ring, whichmust fit on the outside of the knife tube 200, is between about 2.8 mmand about 3.7 mm, particularly between about 3.15 mm and about 3.175 mm.In a more particular embodiment, the inner diameter 44 is about 3.15 mm.

In a particular embodiment, the outer diameter 45 of the alignment ringis between about 6 mm and about 10 mm, preferably between about 7.569 mmand about 7.671 mm. In a more preferred embodiment, the outer diameter45 is about 7.62 mm.

As shown in FIG. 4B, in one embodiment, the distance 46 between theinner opening of the alignment ring and the flattened surface 252, on aline perpendicular to the flattened surface 252, is between about 0.25mm and about 0.5 mm, preferably between about 0.330 mm and about 0.432mm. In more preferred embodiment, the distance 46 is about 0.381 mm.

Referring to FIG. 4C, showing a side view of the alignment ring, andFIG. 4D, showing a view from the top of the alignment ring, in oneembodiment, the alignment ring 250 has a thickness 47 of between about1.0 mm and about 4.0 mm. In a particular embodiment, the thickness 47 isbetween about 2.0 mm and about 3.0 mm. In a more particular embodiment,the thickness 47 is about 2.54 mm.

The hook blade 100 and the endoscopic knife assembly 300 described abovemay be readily applied to surgical procedures such as, but not limitedto, carpal tunnel release; cubital tunnel release, plantar fasciarelease, lateral release for patella realignment, release of radialtunnel, release of pronatar teres, release of trigger finger, release oflacertous fibrosis, release of the extensor tendons for lateralepicondylitis (tennis elbow), release of medial epicondylitis (golfer'selbow), and release of fascial compartments in the upper and lowerextremity.

Another aspect of the present application relates to an instrument kitfor implementing an endoscopic surgical procedure. The instrument kitcontains an endoscopic knife assembly having a hook blade and a cannulaguide member including a longitudinal bore having open proximal anddistal ends and an open slot extending along the length thereofcommunicating with the open ends, and an elongate insertion member thatis slidably receivable within the cannula guide member and is configuredso that at least portions thereof conform with the open distal end andthe open slot of the guide member to form a smooth exterior surface incombination therewith.

In one embodiment, the instrument kit further includes an endoscopesized for insertion into the cannula guide member for directvisualization of an operative site.

In another embodiment, the endoscope is capable to carry a cuttinginstrument at a leading end.

In another embodiment, the instrument kit further includes a secondcutting instrument mountable to the leading end of the endoscope.

In another embodiment, the instrument kit further includes a secondendoscope with a second cutting instrument mounted at a leading end ofthe second endoscope. The second endoscope is insertable into thecannula guide member such that the cutting instrument protrudes throughthe open slot in the cannula guide member. The second cutting instrumentmay be an endoscopic knife assembly having a hook blade or an endoscopicknife assembly having another type of blade including, but not limitedto, a blade comprising an upper and a lower cutting surface on theforward edge of the blade, said cutting surfaces meeting at an angle ata crotch.

In another embodiment, the instrument kit further includes a depth gaugemountable to a leading end of the endoscope.

In another embodiment, the instrument kit further includes a rasp membersized for insertion into the cannula guide member.

In another embodiment, the instrument kit further includes a lockingdevice capable of locking the endoscope and the cannula guide memberinto mutually fixed positions.

In another embodiment, the instrument kit further includes a stop devicemountable on the cannula guide member to prevent excessive penetrationat a surgical site by the cutting instrument.

In another embodiment, the instrument kit further includes a curveddissector.

Another aspect of the present application relates to a method forimplementing a uniportal endoscopic surgical procedure using anendoscopic knife assembly having a hook blade of the presentapplication. In one embodiment, the method includes the steps of makingan incision on a patient in need of such endoscopic surgical procedureat a location proximate an operation site to establish an entry portal,inserting an elongate insertion member into a longitudinal bore of anelongate transparent cannula having open proximal and distal ends and anopen slot extending along the length of the cannula, the elongateinsertion member being configured to form a smooth exterior surface atthe open distal end of the cannula when fully inserted into the cannula;introducing the distal end of the cannula/insertion member combinationinto the entry portal and advancing the combination a predetermineddistance relative to the operation site; withdrawing the insertionmember while permitting the cannula to remain in place at the operationsite; inserting a first endoscope into the cannula for directvisualization of anatomic structures surrounding the cannula andpositioning of the cannula at the operative site; withdrawing the firstendoscope from the cannula; mounting an endoscopic knife assembly havinga hook blade on a leading end of a second endoscope; inserting theendoscope with the endoscopic knife assembly having a hook blade intothe cannula such that the hook blade protrudes into the open slot in thecannula, and advancing the second endoscope so that the endoscopic knifeassembly having a hook blade moves distal to and is in contact with atarget tissue at the operation site; operatively engaging the targettissue with the endoscopic knife assembly having a hook blade whilewithdrawing the latter back towards the cannula under directvisualization through the second endoscope so as to perform an operativeprocedure on the target tissue; withdrawing the second endoscope and theendoscopic knife assembly having a hook blade from the cannula;withdrawing the cannula through the entry portal; and suturing theincision.

In one embodiment, the first endoscope and the second endoscope are thesame endoscope. In another embodiment, the first endoscope and thesecond endoscope are different endoscopes.

The cannula can be inserted into the tissue through a small opening andadvanced to a surgical site, thus forming a passageway towards thesurgical site. The passageway allows the insertion of the endoscope andendoscopic knife assembly having a hook blade to the surgical sitewithout further damages to the surrounding tissues. The endoscopic knifeassembly having a hook blade and a slotted cannula can be used inendoscopic surgical procedures such as carpal tunnel release, cubitaltunnel release, plantar fascia release, lateral release for patellarealignment, release of the extensor tendons for lateral epicondylitis(tennis elbow), release of the posterior and other compartments of theleg, and the forearm fascial release for fascial compartment syndrome.

The contents of all references, patents and published patentapplications cited throughout this application, as well as the Figuresand Tables are incorporated herein by reference.

The above description is for the purpose of teaching the person ofordinary skill in the art how to practice the present invention, and itis not intended to detail all those obvious modifications and variationsof it which will become apparent to the skilled worker upon reading thedescription. It is intended, however, that all such obviousmodifications and variations be included within the scope of the presentinvention, which is defined by the following claims. The claims areintended to cover the claimed components and steps in any sequence whichis effective to meet the objectives there intended, unless the contextspecifically indicates the contrary.

1. A hook blade for an endoscopic knife assembly, comprising: an armhaving a forward edge, a trailing edge and an upper cutting surfacelocated on the trailing edge; a main body having an upper edge, a loweredge, a distal section, a proximate section, and a lower cutting surfacelocated on the upper edge of the distal section; wherein the distalsection of the main body angles downward from the proximate section ofthe main body, forming a downward angle with the proximate section ofthe main body, wherein the arm protrudes from the distal section of themain body and extends back towards the main body in a hook-like manner,forming a hook angle with the proximate section of the main body, andwherein the upper cutting surface and the lower cutting surface meets ata crotch forming a cutting angle between the two cutting surfaces. 2.The hook blade of claim 1, wherein the hook angle is between about 55degrees and about 75 degrees.
 3. The hook blade of claim 2, wherein thehook angle is about 65 degrees.
 4. The hook blade of claim 1, whereinthe cutting angle is between about 40 degrees and about 60 degrees. 5.The hook blade of claim 4, wherein the cutting angle is about 50degrees.
 6. The hook blade of claim 1, wherein the downward angle isbetween about 150 degrees and about 175 degrees.
 7. The hook blade ofclaim 6, wherein the downward angle is between about 165 degrees.
 8. Thehook blade of claim 1, wherein the proximate section of the main bodyhas a tapered end.
 9. The hook blade of claim 1, wherein the main bodycomprises a notch on the lower edge to engage with a knife tube.
 10. Thehook blade of claim 1, wherein the arm comprises an upper radius on theupper end of the forward edge to prevent the forward edge from damagingtissue as the hook blade is advanced from a cannula.
 11. The hook bladeof claim 10, wherein the arm further comprises a lower radius on thelower end of the forward edge to prevent the forward edge from damagingtissue as the hook blade is advanced from a cannula.
 12. The hook bladeof claim 1, wherein the hook blade has a total vertical height in therange of about 4 mm to about 5 mm.
 13. An endoscopic knife assembly,comprising: a knife tube having a distal end and a proximate end; a hookblade attached to the distal end; and an alignment ring attached nearthe proximate end, wherein the hook blade comprises an arm having aforward edge, a trailing edge and an upper cutting surface located onthe trailing edge; a main body having an upper edge, a lower edge, adistal section, a proximate section, and a lower cutting surface locatedon the upper edge of the distal section; wherein the distal section ofthe main body angles downward from the proximate section of the mainbody, forming a downward angle with the proximate section of the mainbody, wherein the arm protrudes from the distal section of the main bodyand extends back towards the main body in a hook-like manner, forming ahook angle with the proximate section of the main body, and wherein theupper cutting surface and the lower cutting surface meets at a crotchforming a cutting angle between the two cutting surfaces.
 14. Theendoscopic knife assembly of claim 13, wherein the knife tube comprisesone or more slots at the proximate end for the attachment of a lockingassembly to the knife tube and alignment ring.
 15. The endoscopic knifeassembly of claim 13, wherein the slots are located on a plane that isperpendicular to the hook blade attached to the distal end of the knifetube.
 16. The endoscopic knife assembly of claim 13, wherein the knifetube is marked on the top or side surface with gradations.
 17. Theendoscopic knife assembly of claim 13, wherein the alignment ringcomprises a flattened surface that is positioned perpendicular to thehook blade attached to the distal end of the knife tube.
 18. Theendoscopic knife assembly of claim 13, wherein the hook blade is weldedto the knife tube.
 19. An instrument kit for implementing an endoscopicsurgical procedure comprising: an endoscopic knife assembly comprising ahook blade, a knife tube and an alignment ring, wherein the bladecomprises an upper cutting surface located on a trailing edge of an armand a lower cutting surface located on an upper edge of a main body ofthe blade, the cutting surfaces meeting at an angle at a crotch; and aslotted cannula for endoscopic surgical procedures, wherein theendoscopic knife assembly is insertable into the slotted cannula. 20.The instrument kit of claim 19, wherein the main body of the bladecomprises a notch on a lower edge of the main body to engage with theknife tube.
 21. A method for a performing a operative procedure on atarget tissue in a subject, comprising: establishing an entry portal,inserting a cannula having open proximal and distal ends, inserting anendoscope into the cannula, said endoscope comprising an endoscopicknife assembly having a hook blade, advancing said endoscope so that thehook blade moves distal to and is in contact with the target tissue, andoperatively engaging the target tissue with the hook blade.
 22. Themethod of claim 21, wherein said operative procedure is an endoscopicsurgical procedure selected from the group consisting of carpal tunnelrelease, cubital tunnel release, plantar fascia release, lateral releasefor patella realignment, release of the extensor tendons, release of theposterior and other compartments of the leg, and forearm fascialrelease.
 23. The method of claim 21, wherein said method furthercomprises a step of withdrawing the hook blade back towards the cannulato perform the operative procedure on the target tissue.
 24. The methodof claim 21, wherein said cannula comprises an open slot extending alongthe length of the cannula.
 25. The method of claim 21, wherein saidinserting of said endoscope comprising an endoscopic knife assemblyhaving a hook blade is preceded by the insertion of another endoscopecomprising a means for visualization of the target tissue.
 26. Themethod of claim 25, wherein said cannula is a clear cannula.
 27. Themethod of claim 26, further comprising visualization of anatomicstructures surrounding the cannula.
 28. The method of claim 21, whereinsaid establishing an entry portal comprises making an incision.